There is ample evidence that improper and infrequent use of personal protective equipment (PPE) when handling chemotherapy leads to hazardous drug exposure, which has been linked to cancer, reproductive problems, and serious central nervous system, respiratory, and skin conditions. Nurses in ambulatory oncology settings are at high risk given the large volume of drugs administered. Extensive preliminary data show frequent hazardous drug exposure in the ambulatory oncology setting, low perceived risk of drug exposure, inadequate knowledge about PPE use, and low PPE use by nurses, in addition to differences in organizational factors between exposed and unexposed nurses. Despite this knowledge, there is an absence of tested interventions aimed at increasing PPE use among nurses who handle hazardous drugs. An audit and feedback intervention evaluation is appropriate given the team's ability to conduct web-based surveys on PPE use and collect plasma from nurses to detect the presence of 22 hazardous drugs using highly sensitive and specific tandem liquid chromatography/mass spectrometry methods. The long-term goal is to improve the quality and safety of chemotherapy administration to protect heath care workers. The specific project objective is to evaluate the efficacy of an audit and feedback intervention to improve PPE use by nurses who handle hazardous drugs in the ambulatory oncology setting. This project will pursue three specific aims: 1) Evaluate the efficacy of an audit and feedback intervention to improve recommended use of PPE; 2) Determine whether the intervention effects on PPE use are mediated by knowledge about PPE use and perceived risk of hazardous drug exposure, and; 3) Determine whether the intervention effects on PPE use are moderated by personal (experience, education, certification) and organizational factors (workloads, practice environments, safety organizing). To achieve these aims, 382 nurses employed in 11 oncology centers will participate in a cluster randomized controlled trial. Sites will be randomized so participants will receive a one-hour web-based educational module on hazardous drug safe handling with quarterly email reminders about the educational content (control) or the web-based educational module plus quarterly feedback on hazardous drug spills and drug levels measured in the study population (treatment). The hypothesis is that nurses in sites who receive the treatment will report significantly higher PPE use compared to nurses in sites assigned to receive the control. Data will also identify organizational factors that can be targeted for future interventions. The project's innovation is the paradigm shift from descriptive to intervention research and the use of novel techniques to measure hazardous drug exposure in nurses with sensitive, specific, and efficient methods. This project will be one of the few, if only, experimentally-tested intervention studies designed to increase PPE use among nurses who administer hazardous drugs. The project is significant because it will generate essential data to change the current practice of PPE use in an understudied, high-risk setting.